The Motor Effect

motor effect meaning

force on a current carrying wire in a magnetic field

force condition

wire must be at an angle to the magnetic field

no force condition

wire parallel to magnetic field

force direction rule

given by fleming’s left hand rule

left hand rule

thumb is force, first finger is field, second finger is current

field direction

from north to south

current direction

direction of conventional current, positive to negative

force size factors

magnetic field strength, current size, length of wire

increase force

increase current, increase field strength, use longer wire

magnetic flux density meaning

measure of field strength, symbol B

force formula

F = B I L

units

force in N, B in T, current in A, length in m

coil in field

opposite sides of coil experience opposite forces

rotation effect

forces create a turning moment, causing rotation

electric motor meaning

device that uses motor effect to produce rotation

split ring commutator

reverses current every half turn to keep motor spinning

brushes meaning

maintain electrical contact with commutator

key idea

current + magnetic field = force